Conventionally, array antennas which include a substrate, antenna elements, and feeder lines are known. The substrate is a plate made of a dielectric material having a given size, and the antenna elements and the feeder lines are arranged on the substrate. The antenna elements are arranged in line in one direction (hereinafter, referred to as the array direction). The feeder lines supply to the antenna elements radio waves inputted from outside. Patent Documents 1 and 2 disclose such kind of array antennas.
In the array antenna of Patent Document 1, the feeder lines are connected to the antenna elements from the array direction (from the right side in FIG. 1). In Patent Document 1, the feeder lines are connected in the same direction to all the antenna elements.
In the array antenna of Patent Document 2, on a right side of the center of the substrate in longitudinal directions thereof, the feeder lines are connected to the antenna elements from the left side (center side). On the other hand, on the left side of the center of the substrate in the longitudinal directions, the feeder lines are connected to the antenna elements from the right side (center side).